Lavernock fossil helps untangle 200 years of confusion over ancient fish

A fossil jaw found on Lavernock Beach has helped researchers distinguish between two ancient fish whose remains had confused scientists for generations. Amgueddfa Cymru plans to display the specimen at National Museum Cardiff later in 2026.

The jaw preserved developing teeth. Comparing it with museum specimens helped a team from Amgueddfa Cymru, Bristol University and Stuttgart’s natural history museum show that remains previously grouped together came from different fish.

Why a jaw made the difference

Teeth collected around the Bristol Channel had proved difficult to classify. Some early researchers even mistook them for amphibian remains, the museum explained in its announcement on 25 September.

The study examines Birgeria and Saurichthys from the Late Triassic. Its authors describe differences in their anatomy and ways of hunting that allowed them to live in the same environment. Their reconstruction depicts two distinct predatory fish, rather than one animal represented by all the teeth.

Where readers can see the evidence

The research paper was published online in the Journal of Vertebrate Paleontology on 24 September 2026. It links to CT data, three-dimensional models and a list of museum specimens, giving other researchers material with which to examine the findings.

The museum has not announced a date for the Cardiff display. The discovery concerns fish that lived more than 200 million years ago; the nearly 200-year mystery refers to the history of research into their remains.